Solar sizing for homes that lose power
Size your system
Three steps. Results update as you type.
Step 1
Your hours without power
Tap the hours you lose the grid. The amber edge traces the day’s sun: where your mint block sits with no amber above it, those hours come entirely out of the battery.
Use the arrow keys to move and Enter or Space to toggle an hour.
0 h with sun6 h without sun
Of your 6 outage hours, 0 fall in daylight, so panels can feed the house directly. The other 6 come out of the battery.
Step 2
What you want to keep running
Hours are pre-filled with realistic use for each appliance during a 6 h outage. Adjust them if your case differs.
Air conditioning triples both the bank and the array. Before buying, check whether you can back up a single room or switch to an inverter mini split.
Add another appliance
Step 3
Your site settings
The defaults hold for much of the tropics and subtropics. Adjust them to your location.
Look up your city in the Global Solar Atlas and adjust: it changes array size more than any other input.
Optional. Used only to tell you how close you are.